• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.274-277
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• 2004

Production of green fluorescent protein (GFP) as a model foreign protein using different culture scales under co-expression of Vitreoscilla hemoglobin (VHb) in the industrial Escherichia coli strain W3110 (a K12 derivative), was examined. It was found that the VHb co-expressing W3110, exhibited an exceptional and sustained production ability during cell cultures using different scales, while the VHb non-expressing strain showed variable production levels. This high and sustained production ability indicates that the VHb co-expressing E. coli W3110, could be successfully employed for practical large-scale production cultures without the need for serious consideration of scale-up problems.

• Journal of Microbiology and Biotechnology
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• v.30 no.10
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• pp.1592-1596
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• 2020

The aerobic growth and metabolic performance of Escherichia coli strains BL21 and W3110 were studied when the Vitreoscilla hemoglobin (VHb) was constitutively expressed in the chromosome. When VHb was expressed, acetate production decreased in both strains and was nearly eliminated in BL21. Transcriptional levels of the glyoxylate shunt genes decreased in both strains when VHb was expressed. However, higher transcription of the α-ketoglutarate dehydrogenase genes were observed for W3110, while for BL21 transcription levels decreased. VHb expression reduced the transcription of the cytochrome bo₃ genes only in BL21. These results are useful for better selecting a production host.

• Journal of Food Hygiene and Safety
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• v.16 no.2
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• pp.89-95
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• 2001

This study was conducted to find material having antibacterial activity. The effects of preservatives, antibiotics and oriental medicines on growth of teated microorganisms were investigated. The growth of all tested bacteria was inhibited by water extract of Schizandra chinensis. Antibacterial activity on the concentration of Schizandra chinensis extract was tested. The growth of Escherichia coli W3110, Enterobacter colacae MG82 and Salmonella typhimurium was extraordinarily inhibited by more than 0.2% concentration of Schizandra chinensis extract. The specific growth rate of Escherichia coli W3110, Enterobacter cloacae ME82 and Salmonella typhimurium under control conditin had mean values of 0.514(hr￣), 0.381(hr￣) and 0.489(hr￣), respectively. When 0.2% of Schizandra chinensis extract was added, specific growth rates of Escherichia coli W3110, Enterobacter colacae MG82 and Salmonella typhimurium wre decreased, compared to contorl, in 1.26, 2.23 and 1.50 fold, respectivley. Minimal inhibiotory concentration of Schizandra chinensis extract was 0.25% on the tested microorganisms The growth of Enterobacter cloacae MG82 was more inhibited by Schizandra chinensis extract than other tested microorganisms.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.754-757
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• 2001

Expression of the vhb gene encoding bacterial hemoglobin (VHb) from Vitreoscilla has been used to improve recombinant cell growth and enhance product formation under microaerobic conditions because of its ability to enhance oxygen use. We coexpressed GFP and VHb in Escherichia coli BL21 and W3110, and compared with GFP control which was not expressed VHb. We used nar oxygen-dependent inducible promoter for VHb expression. The GFP amounts in E. coli expressed VHb was about five fold higher than in the control Fluorescence intensity was increased about two fold.

• ALGAE
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• v.17 no.3
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• pp.195-199
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• 2002

We investigated the association of Chlorella vulgaris and E. coli W9110 in removal of total organic carbon with the lab-scaled continuous river water flow system (CRWFS). Artificial wastewater was applied at two levels of organic carbon concentration; 1,335 $mg{\cdot}l^{-1}$ in the treatment (T)-1 and 267 $mg{\cdot}l^{-1}$ in T-2. The highest densities of C. vulgaris were $8.3{\times10^6\;cells{\cdot}ml^{-1}$ in T-1 and $6.9{\times}10^6\;cells{\cdot}ml^{-1}$ in T-2. The maximum densities of E. coli W3110 were $2.0{\times}10^8$ clony forming unit (CFU)${\cdot}ml^{-1}$ in T-1 and $3.9{\times}10^8\;CFU{\cdot}ml^{-1}$ in T-2. The densities increased during the first 11 days in T-q and 4 days in T-2, and decreased rapidly till 35th day, then increased slightly afterwards. This trend was prominent in T-2. It was inplied that wider range of nutrients was required in the growth of heterotrophic bacteria in T-2 than in T-1. The algal biomass should be increased effectively for the successful removal of organic carbon.

• Journal of Microbiology and Biotechnology
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• v.21 no.4
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• pp.374-378
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• 2011

To find alternative genetic resources for D-serine dehydratase (E.C. 4.3.1.18, dsdA) mediating the deamination of D-serine into pyruvate, metagenomic libraries were screened. The chromosomal dsdA gene of a wild-type Escherichia coli W3110 strain was disrupted by inserting the tetracycline resistance gene (tet), using double-crossover, for use as a screening host. The W3110 dsdA::tet strain was not able to grow in a medium containing D-serine as a sole carbon source, whereas wild-type W3110 and the complement W3110 dsdA::tet strain containing a dsdA-expression plasmid were able to grow. After introducing metagenome libraries into the screening host, a strain containing a 40-kb DNA fragment obtained from the metagenomic souce derived from a compost was selected based on its capability to grow on the agar plate containing D-serine as a sole carbon source. For identification of the genetic resource responsible for the D-serine degrading capability, transposon-${\mu}$ was randomly inserted into the 40-kb metagenome. Two strains that had lost their D-serine degrading ability were negatively selected, and the two 6-kb contigs responsible for the D-serine degrading capability were sequenced and deposited (GenBank code: HQ829474.1 and HQ829475.1). Therefore, new alternative genetic resources for D-serine dehydratase was found from the metagenomic resource, and the corresponding ORFs are discussed.

• Journal of Environmental Science International
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• v.12 no.8
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• pp.847-852
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• 2003

It was examined carefully that the bacterial die-off between Chlorella vulgaris and E. coli. W3110 was tested through adding TOC (total organic carbon) with the lab-scaled continuous river water flow system (CRWFS). Artificial synthetic wastewater was applied at two levels of organic carbon concentration; 1,335 mg/l in treatment type 1 and 267 mg/l in type 2. In both types, the population densities of Chlorella vulgaris were similar in a maximum 8.25 ${\times}$ 10$\^$6/ cells/ml (type 1) and 6.925 ${\times}$ 10$\^$6/ cells/ml (type 2). The maximum densities of E. coli. W3110 were 2.0 ${\times}$ 10$\^$8/ colony forming unit (CFU)/ml in type 1 and 3.9 ${\times}$ 10$\^$8/ CFU/ml in type 2. The densities increased for 11 days in type 1 and 4 days in type 2, then decreased rapidly till the 35th day, then slightly increased again. This trend was prominent in type 2. It implied that a wider range of nutrients was required in the growth of heterotrophic bacteria in type 2 than in type 1. We could not expect successful bacterial die-off if the wastewater retention time was not furnished sufficiently.

• Microbiology and Biotechnology Letters
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• v.19 no.6
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• pp.583-587
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• 1991

A threonine overproducer, E. coli TF427, which is resistant to threonine analogue, a-amino-(3-hydroxyvaleric acid (AHV), and requires both methionine and isoleucine was developed by the mutations of E, coli W3110 using N-methyl-Nf-nitro-N-nitrosoguanidine (NTG) and UV. The E. coli TF427 produced 46.5 gll of threonine in a 5-L jar fermentor after 44 hr cultivation. The aspartokinase I of TF427 was not inhibited by threonine, and its synthesis was not repressed by threonine plus isoleucine.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.576-576
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• 2003

• Journal of Microbiology and Biotechnology
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• v.26 no.8
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• pp.1452-1456
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• 2016

Overexpression of the genes encoding phosphoeneolpyruvate carboxykinase (pckA) and NAD-dependent malic enzyme (maeA) facilitates higher intracellular ATP and NAD(P)H concentrations, respectively, under aerobic conditions in Escherichia coli. To verify a hypothesis that higher intracellular energy reserves might contribute to H₂ fermentation, wild-type E. coli strains overexpressing pckA and maeA were cultured under anaerobic conditions in a glucose minimal medium. Overexpression of pckA and maeA enabled E. coli to produce 3-times and 4-times greater H₂ (193 and 284 nmol, respectively) than the wild type (66 nmol H₂). The pckA and maeA genes were further overexpressed in a hydrogenase-3-enhanced E. coli strain. The hydrogenase-3-enhanced strain (W3110+fhlA) produced 322 nmol H₂, whereas the ATP-enhanced strain (W3110+fhlA+pckA) produced 50% increased H₂ (443 nmol). Total H₂ in the NAD(P)H-enhanced strain (W3110+fhlA+maeA) was similar to that in the control strain at 319 nmol H₂. Possible explanations for the contribution of the increased cellular energy reserves to the enhanced hydrogen fermentation observed are discussed based on the viewpoint of metabolic engineering strategy.